Actuator



Feb, 10, 1942. s. SVENSON 2$272,533

ACTUATOR Filed Dec. 17, 1938 2 Sheets-Sheet 1 ATTORNEY Feb. 10, 1942. s. SVENSON 2,2?2 533 ACTUATOR Filed Dec. 1.7, 1938 2 Sheets-Sheet 2 lA/VE TOR JrzwJVa/roA /f DECEASED av damn 61 54 60 HDHM/TR/X ATTORNEY Patented Feb. 10, 1942 UNITED STATES PATENT OFFICE ACTUATOR and Carl Svenson Application December 17, 1933, Serial No. 246,378

2 Claims.

The invention relates to actuators of the general type shown in Patent No. 2,093,689, issued to Sven Svenson on September 21, 1937, entitled Motor actuator, and is particularly concerned with a means for electrically operating a device of the character of a stapling machine, for example, automatically upon the insertion into the machine of a sheet or sheets to be stapled or stamped or comparably operated upon.

Where only a few sheets of easily perforable paper are to be stapled together, the amount of power required is relatively small and the difliculties 'of supplying electrical actuation ar not great. 'But when the number of sheets to be stapled together is large and the paper is not readily perforable, then the amount of power instantaneously required becomes very great indeed, so that there is diificulty in supplying a source of power which is acceptable for desk or office use and which does not require so much current as to give trouble with electrical contacts and other parts of the circuit, yet which is of a reasonable character from the standpoints of cost of manufacture, maintenance and operation. But even a machine which is readily usable under heavy duty conditions and is particularly designed therefor may not give entirely satisfactory service if it is indiscriminately utilized for very light operations, such as stapling only One or two sheets.

It is therefore an object of the invention to provide an actuator which with equal facility is usable with very light loads or very heavy loads.

Another object of the invention is to provide an actuator which is of reasonable size and character yet is capable of exceedingly heavy duty operation.

An additional object of the invention is to provide an actuator which is initially energized by the insertion of a sheet to be treated and which has adequate power so controlled as to perform heavy duty or light duty operations.

Another object of the invention is to provide an actuator which is useful in connection with various appliances other than staplers, such as stamps, perforators and the like.

The foregoing and other objects are attained in the embodiment of the invention illustrated in the drawings, in Which Fig. 1 is a side elevation of an actuator in accordance with the invention;

Fig. 2 is a front elevation of the device shown in Fig. 1;

Fig. 3 is a side elevation of the actuator with the enclosing casing removed;

' ing housing 8 is detachably mounted.

Fig. 4 is a plan of the structure shown in Fig. 3;

Fig. 5 is a cross-section on a longitudinal, vertical, central plane, indicated by the line 5-5 of Fig. 4, showing the actuator in de-energized position;

Fig. 6 is a view similar to Fig. 5 yet showing the actuator in energized position.

In its preferred form, the actuator of this invention is usable in connection with a stapling machine which is mounted on a base in connection with the actuator. the actuator itself preferably including an electromagnetic coil having a pair of armatures which are simultaneously energized to move into the coil and which are both coupled to a linkage for actuating the stapler.

While the actuator of this invention is by no means restricted to use with stapling machines, or restricted to use only with a special type of stapling machine, it is convenient to describe it in connection therewith and hence it is so illustrated herein. In the present embodiment there is included a base 6 having a plurality of supporting feet 1 and on which a removable enclos- The housing is provided along its forward portion with 'a receiving slot 9 into which material such as a plurality of sheets to be stapled can be inserted. The sheets are pushed into the slot 9 manually until they abut a finger 'H in their path of advance, which energizes the device to effectuate a stapling operation, following which the sheets are withdrawn. The cycle can be repeated with subsequent insertion of sheets.

Within the casing 8 there is situated a stapling machine [2 which is a complete commercial article having its own base l3 provided with feet which fit into suitable sockets in the base 6. The stapler is completely actuated by depression of a lever l! which pivots about a hinge E8 on the base 13 and which, when the stapler i not utilized in this environment, is ordinarily actuated by manual depression of a pad 19.

In accordance with the invention, there is secured to the base 6 a pair of uprights 2| and 22, spaced apart so that they receive the stapler l2 between them, yet extending upwardly to provide bearing supports 23 for a cross-shaft 24. Projecting from the cross-shaft are radial arms 26 and 2? which between them support a rotating roller 28 abutting the upper surface of the lever ii. The shaft 23 has a squared end 29 to which a hand crank (not shown) can be attached through an aperture 3| in the side of the housing 8, so that upon operation of the hand crank the shaft 24 is rotated and by depression of the roller 28 the stapler is manually actuated.

This manual actuation is not ordinarily utilized, and in order to provide power actuation, the shaft 24 carries a pair of arms 32 and 33 between them carrying a swivel block 34 which is rotatable on a cross-pin 36 mountable alternatively in either of two pairs of apertures 31 and 38 in the arms 32 and 33. The block 34 has an interiorly threaded extension 39 into which is screwed a pitman rod 4| having a flattened terminus 42' extending into the forked end 43 of an armature bar 44 to which the pitman is articulated by a pivot pin 46. The armature bar is preferably square in transverse cross-section and at its opposite end is connected by a pin 41 to an armature 48 preferably fabricated of a plurality of metal sheets held in a pack by rivets 49. The armature 48 is preferably itself rectangular in transverse cross-section and is slidable within a rectangular tube of non-magnetic material. Likewise slidable within the tube 5| is a second armature 52 fabricated of a bundle of metal plates se ured by rivets 53 and having an interior recess 54 to accommodate the pitman 4| and the bar 44. Fastened to the armature 52 is a pair of pitmans 5 and 51 each of which is secured by a pin 58 and both of which extend to pivotal connections by pins 59 and BI to extensions of the arms 26 and 21 wherein a pair of apertures 62 and 63 are provided for alternative utilization,

In accordance with the invention, there is pro vided. means for electromagnetically energizing the two armatures 48 and 52 simultaneously. The arrangement of such means is so that the center of the electromagnetic field substantially coincides with the center of the tube 5|. For that reason, around the tube 5| is provided an electromagnetic coil 66 with which cooperates a field frame 61 preferably made of laminated metal sheets secured together by screw fastenings 68 and provided with feet 69 for mounting the assembly on the base 6. When the coil 66 is energized, the two armatures 48 and 52 are moved toward each other and toward the center of the tube 5| so that the pitmans 56 and 51 and the pitman rod 4| are simultaneously actuated in opposite directions to rotate the shaft 24 and thus to actuate the stapler. While the speed of operation of the armatures 48 and 52 can be somewhat regulated by the air cushion or dashpot effect due to the movement of the armatures into the interior of the tube, there is preferably provided no material restriction by this means and consequently there is afforded a passage 1| in the bar 44 to establish communication between the chamber 12 within the tube and between the armatures and the exterior, so that air may flow freely inwardly and outwardly from such chamber, although the passage can be restricted if de-- sired and such restriction can be operable equally in both directions of airflow or can have more effect in one direction of airflow so that one directional movement of the armatures is restricted more than the other.

With this arrangement, when the coil 66 is energized the armatures 48 and 52 are pulled with a great force into a location where the flux is of maximum density, so that with a small expenditure of electric current the stapler is effectively actuated. Furthermore, the relationship of the lever arms 26 and 32' is such that the force exerted by the electromagnet is correctly related to that required by the stapler, so that the mechanism is given a thorough and satisfactory actuation.

In order that the coil 66 will be suitably energized upon insertion into the stapling machine of a sheet to be operated upon, there is provided an electric circuit and associated instrumentalities which will produce the requisite result. Current from a suitable source is conducted to the machine through a lead which is connected to the coil 66. From the coil a lead extends to a. brush 18 which is mounted on a block 19 secured between a pair of brackets 8| and 82 mounted on the field frame 61. In rotatable contact with the brush 18 is a switch barrel 88 preferably fabricated of insulating material and mounted on a pin 83 journaled in the brackets 8| and 82. Forming an element of the barrel 82 is a metallic conducting plug 84 with which the brush 18 is adapted to contact. Axially displaced from the brush 18 is a brush 86 likewise mounted on the block 18 and forming a continuation of the circuit.

To ensure that the interruption of the circuit to the coil 66 is made at the appropriate time despite the fact that perhaps the material being treated is not promptly withdrawn, and despite variations in the thickness of the materials which might vary the stroke of the stapling mechanism, there is provided a means which is responsive to the actuation of the machine for interrupting the circuit. To this end, on the rod 4| is mounted a collar I46 which is adjustably positionable by manipulating a set-screw I41, and there is likewise mounted on the rod a loose sleeve I48 which is separated from the collar by an interposed cushion washer I49. Normally the sleeve and the collar are urged together by a coil spring I5| one end of which engages a pin I52 in the collar I46 and the other end of which engages a pin I53 in the sleeve I48.

The sleeve I48 is in the nature of an inertia weight, so that when the rod 4| is rapidly accelerated toward the left in Fig. 3 the weight I48 is accelerated therewith; yet when the rod 4| stops suddenly during the stapling operation, the weight I48 continues to slide along the rod 4|. This tensions the spring I5 I, and the weight I48 is subsequently returned by the spring tension. In the interim, however, the weight I48 comes into abutment with a loop I54 which encompasses the rod 4| and is formed at the end of a rod I56 connected by a pivot pin I 51 to an arm I58 extending from the drum 8|]. A felt washer I59 is interposed as a cushion between the loop I54 and the swivel block 39.

The relationship of the parts is such that when the coil is energized and the rod 4| is actuated, the felt washer I59 is translated with the rod 4|, yet the loop I54 retains its position. But as soon as the rod 4| stops, having completed the stapling operation, the weight I48 continues on and strikes the loop I54 translating it and the rod I56 toward the left in Fig. 3, thus rotating the contact drum 80. This rotation causes the conductor 84 to ride from under the conductor arms 18 and 86, thereby breaking the circuit and de energizing the coil 66. The rotation of the drum is suflicient to bring a groove |6I therein into position beneath the arcuate ends of the arms 18 and 86 so that the drum is held in contact-open position until such time as the standard return spring mechanism in the stapling device moves the arm I1 upwardly, rotates the shaft 24 in a clockwise direction as seen in Fig. 3, restores the parts to their original position, and the felt collar I59 aga-in abuts the loop I54 and drives the rod [56 toward the right in Fig. 3 so that the drum 80 is rotated back into a position in which the conductor 85 is again in abutment with the contact arms 18 and 86. Thus the circuit is always broken by the inertia member I 58 and without regard to the thickness of the material being stapled or otherwise treated, so that the interruption of the electric circuit takes place without regard to the character of the material being treated or the character of the stapling operation.

What is claimed is:

1. An actuator comprising a frame, a shaft journalled on said frame and having a pair of opposed cranks thereon, a sleeve mounted on said frame wholly at one side of the shaft with its axis at right angles to and in the same plane with the axis of said shaft means for producing an electromagnetic field around the center of said sleeve, a pair of armatures mounted to slide within said sleeve, the armature nearer said shaft having an aperture therethrough, a single link pivotally connecting said nearer armature to one of said cranks, and another single link working freely through said aperture and pivotally connecting the farther one of said armatures to the other of said cranks, the angular relationship of said links and said cranks being such that the operating leverage of said armatures is greater near operated position than at their unoperated position.

2. An actuator comprising a frame, a sleeve mounted on said frame, means for producing an electromagnetic field around the center of said sleeve, a shaft journalled on said frame beyond one end of said sleeve, the axis of said shaft being disposed substantially at right angles to and intersecting the sleeve axis, opposed cranks carried by said shaft, an armature reciprocable within said sleeve between the center thereof and the sleeve end near said shaft, a single link pivotally connecting said armature to one of said cranks, a

second armature reciprocable within said sleeve between the center thereof and the sleeve end remote from said shaft, a second link pivotally connecting said second armature to the other of said cranks, the said first mentioned armature being apertured to permit the said second link to reciprocate freely through the first mentioned armature, and the angular relationship of the crank arms and connecting links being such that the operating leverage of said armatures is greater near operated position than at their unoperated position.

SELMA SVENSON, Administratrix of the Estate of Sven Svenson,

Deceased. 

